Electrical switch housing



May 12, 1970- A. F. FIELDS I 5,

ELECTRICAL SWITCH HOUSING Filed March 14', 1968 NVENTOR ALBERT F FIELDS United States Patent 3,511,956 ELECTRICAL SWITCH HOUSING Albert F. Fields, Torrington, Conn., assignor to Dynamics Corporation of America, New York, N.Y., a corporation of New York Filed Mar. 14, 1968, Ser. No. 713,064 Int. Cl. H01h 3/08 US. Cl. 200-172 Claims ABSTRACT OF THE DISCLOSURE A rotary switch housing having an integral knob-shaft arrangement terminating in a split shaft with tapered ends. The tapered ends pass through an orifice in the housing so as to provide a self-locking feature.

This invention relates generally to housing for electrical switches and more particularly to a housing containing an electrical switch of the rotatable type.

Rotary switches for adjusting the speed of small motors or for changing the current to various adjustable loads are in wide usage today. This particular type of switch is especially useful in various domestic appliances such as a Waring Blendor and the like.

Most of the switches in use today include housings and supports which are multi-piece assemblies involving extensive labor to assemble the various parts to the switch. This, of course, adds to the ultimate cost of the particular device, and when this device is a small appliance, the added cost is a significant factor.

An object of the present invention is to provide a simple integral type of housing including a manually turnable knob which includes a self-locking feature.

A further object of the present invention is to provide a housing or electrical switch including a knob which has a self-locking feature upon insertion of the knob into the housing proper.

These and other objects will become apparent from the following description when taken in conjunction with the drawings wherein:

FIG. 1 is a partially cut away side elevational view of the housing and knob;

FIG. 2 is perspective view of the knob and shaft structure;

FIG. 3 is a front view of the knob FIG. 2; and

FIG. 4 is detailed view of the self-locking split shaft feature.

Turning now more particularly to the drawings, there is shown a housing 11 which contains the fixed contacts 36 of an electrical switch. For purposes of clarity the contacts, both fixed and movable, are shown in dotted lines in the drawings. Additionally, no lead lines are shown since the illustrative example uses a very simple wellknown type of rotary switch.

The housing 11 has a cover 12 at the open end thereof through which the rotating shaft 19 of the knob 15 may be inserted. The closed face of the housing 11 has a borehole 13 therethrough for purposes which will be come apparent as the description proceeds.

FIGS. 2 through 4 show the details of the rotating part of the switch. Switch knob 15 may be integral with a cylindrical section 17. A solid cylindrical shaft 19 extends perpendicularly outwardly from the inner face of the cylindrical section 17 substantially centrally therefrom, and terminates in a semi-circular section 22 with a flat face 21.

A split shaft comprising sections 23 and 25 extends axially outwardly from cylinder 19 and semi-cylinder 22. Each of the sections 23 and 25 terminate in outwardly ex- "Ice tending shoulders 31 and 33 which form the extremities of tapered sections 27 and 29.

FIG. 4 shows the split cylinder in solid lines wherein the two sections 23 and 25 are compressed together until the extreme tips of the tapered sections 27 and 29 meet. When the split shaft is forced into the position as shown in FIG. 4, the distance between the outer extremities of the shoulders 31 and 33 is substantially the same as the inner diameter of the borehole 13 in housing 11. Therefore, it can be seen that as the shaft and tapered sections 27 and 29 are directed into the circular lip 14 associated with borehole 13, the split shaft is forced inwardly by a ca-mming action so as to assume the position shown in solid lines in FIG. 4. When the extremities of the shoulders 31 and 33 have passed beyond the front face of the housing 11, the shaft returns to its normal position shown in dotted lines in FIG. 4 and solid lines in FIG. 1, thus locking the integral knob and shaft section into the housing. The only way that the knob and shaft section can be removed from the housing is by manually compressing the two tapered ends 27 and 29 back into the meeting position shown in FIG. 4.

For purposes of illustration, there is shown in FIG. 2 a dotted line representation of a circular body member 35 which is press fit past the split shaft and onto the semicircular shaft 22. The fiat face 21 then provides the mating member for turning body member 35. A finger 37 having a switch contact thereon is adjusted so as to mate with the fixed contact 36 of the switching device within the housing 11.

It will now be apparent that the entire knob and shaft section as shown in FIG. 2 may be molded in one piece so that the essential housing and manual turning knob comprise only two pieces. It will be obvious that the labor involved in assembling this switching device is minimal and, therefore, the costs are substantially reduced over the necessary assembly procedures for known switch housing arrangements.

Additionally, the device is easily disassembled if any minor adjustment or repair is needed or if the shaft requires replacement.

It is to be understood that the above description and accompanying drawings are illustrative only, and that this type of construction may be used with any type of rotary switch and may be modified so as to accommodate the exact details within any switch housing.

I claim:

1. A device for enclosing and operating an electric switch comprising a housing containing fixed switch contacts,

a borehole through one wall of said housing,

a manual control knob,

a first shaft extending substantially perpendicular from said knob and rotatably fitted within said housing, said first shaft receiving a rotatable contact finger,

a split shaft extending outwardly from the end of said first shaft,

a tapered section at the end of each section of said split shaft, said tapered sections forming an extending shoulder adjacent their respective sections of said split shafts,

the distance between the extremities of the shoulders on said tapered sections being substantially the same as the diameter of said borehole,

said tapered sections extending beyond said borehole so as to lock said split shaft within said housing.

2. The device of claim 1 wherein said knob, said first shaft, said split shaft, and said tapered sections are molded as an integral section.

3. A device for containing a rotatable electric switch comprising an enclosed housing for containing the fixed contacts of said switch,

a rotatable shaft passing through the wall of said housing for carrying the movable contact of said switch,

a split shaft extending substantially coaxially outwardly from said rotatable shaft,

a borehole in the wall of said housing in line with said split shaft,

each of said sections of said split shaft terminating in an outwardly extending shoulder and a tapered end section, the distance between the extremities of the shoulders on each of said sections, when compressed together, being substantially the same as the inner diameter of said borehole,

said tapered end sections extending beyond said borehole so as to lock said split shaft 'within said housing.

4. The device of claim 3 further comprising a manual control knob connected to said rotatable shaft.

5. The device of claim 4 wherein said knob, said rotatable shaft, said split shaft, and said tapered end sections form an integral member.

References Cited UNITED STATES PATENTS HERMAN O. JONES, Primary Examiner US. Cl. XR 

